Voltage-regulator.



E. J. BERG.

VOLTAGE REGULATOR. APPLIOATION FILED MAY 12, 1908.

916,982. Patented Apr. 6, 2999.

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UNITED srrrrns rarnnrorrron.

ERNST .rf-Bsne; OF'SGHENECTADY, NEW YORK, ASSIGNOR To GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

, VOLTAGE-REGULATOR.

Specification of Letters Patent.

Batented April 6, 1909.

Application filed May 12, 1908. Serial No. 432,399.

To all whom it-may concern:

'f Be itiknown that I, ERNST J. BERG, a citizen of the United States, residing at Schen .ectady, county of Schenectady, State of v New York, have mvented certain new and usefullinprovements in Voltage-Regulators,

-of which the following is a specification.

. This invention relates to devices for reguf latingv the voltage of currents in electrical Tirrill voltage regulator. 'pens to be desirable to vary the voltage in the exclter circuit of an alternating current supply systems, and it is especially designed for use in connection with the well-known Sometimes it hapgenerator to a greater extent than the Tirrill regulator is capable of producing. The

' or'necessary. The oluect'of the present inventlon is to ordinary range of a Tirrill regulator is about one hundred per cent.

But with some types of ipductor-generators a range of two hundred or more percent. is either advantageous enable this result to be obtained, and to this end the invention consists in providing the exciter circuit, 1n addition to the Tirrlllregulator, withan automatic booster set having a diflerentially-wound motor which drives the booster generator. By this means a'much greater range of voltage can be secured in the field-circuit of the alternatingcurrent generator, as hereinafter set forth. The accompanying drawing is a diagram of circuits illustrating one embodiment of my invention. The mains '1 are fed by analternatingcurrent generator, preferably'of the threeinductor type, of which 2 is the arma- .The field-Winding 3 of this generator isuenerglzed by a direct-current exciter 4 phase :through'the conductors 5; the field strength of said generator being adjustable, to acert'ain extent, by a rheostat 6. The excitor 4 is rovided with a voltage regulator, prefera ly of the Tirrill type; that 1s to say, the

field strength of the exciter is regulated. by

,a'rheostat 7 which can be shunted by a circuit Spontaining the contacts 9. A condenserQO .bridges the contacts 9 so as to suppress'the sparking. A differentially-wound relay 10 controls. said contacts, and one winding 19 of said relay is in series with the floating contacts 11 which are opened and closed by the direct-current main control-magnet 12 and the alternating-current magnet 13, which has two windings energized directly or by tranformers from the main line 1 in u the usual well-known manner.

In one of the leads 5 carrying the exciter current to the alternating-current generator fielding-winding, I interpose a booster set, comprising a generator 14 driven by a motor 15, which. has a field-winding 16 in the exciter circuit. A second field coil 17 is wound upon the coil 16, but in opposition thereto, and this diiierential winding is supplied with a direct current ofco'nstant potential from some suitable source, such, for in resultant of the efiective ampere turns of the two opposing COIlS, and varles with the excitercurrent, but 1n an inverse ratio. When the exciter-current is at its low value, the opposition set up by the coil 16 is low, and the coil '17 produces a strong field,

cordance therewith. The current from the booster generator. 14 is added to that derived from the exciter and the sum ofthe 'two is impressed upon the generator w nding 8, being of a certain predetermined minimum value. tinned and rapidly repeated closures of the relay contacts the exciter voltage rises toits high value, the increase, of the exciter-current in the coil 16 cuts down the effective strength of the excitation due tothe coil 17,

driving the booster motor at a certain speed in ac-- But when by the 0on and this weakening of the motorheld causes the motor to speed up. proportionately, so that the excitation current is further increased. The result of this action is that the electrounotive force impressed upon the generator field winding 3 is much greater than. would be the case if a simple Tlrrlll 'lOO regulator were used! Thus, while the exciter voltage may range between 40 and 80,

it is possible to give the field Winding of the alternating-current generator a voltage ranging from 80 to 240 volts. I

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. 'lhecombination with an alternatingcurrent generator and a normal automatic voltage regulator therefor, of means for automatically increasing the amplitude of regulation by and in accordance with the normal regulation.

2. The combination with an alternatingcurrentgenerator, an exoiter therefor and a normal automatic voltage regulator for the generator, of a series booster generator in one of the leads between the exciter and the generator, and means for varying the speed of the booster by and in accordance with the normal regulation.

3. The combinatlon with an alternating-- erator, of a series booster in one of the leads between the exciter and the generator a difierentia-lly-wound motor for drlving the booster, and means for energizing one of the motor windings from the exciter of the generator and the other from-a source of constant potential.

In witness whereof, I have hereunto set my hand this 11th day of May, 1908.

ERNST J. BERG. Witnesses:

BENJAMIN B. HULL, HELEN ORFoRD. 

